According to the Think Menu, a Medium iced coffee (16 oz) is $2.30, while a large (20 oz) is $2.70. So you're paying 40 cents for the 4 ounce different, except, the extra four ounces don't actually exist.

(Weirdly, the difference between a medium and ice tea is 25 cents, and iced chai is only 20 cents)

We didn't believe it ourselves until we saw VIDEO PROOF of the experiment:

1. On the left, is the Medium, 16 ounce cup full of water; on the right, an empty 20 ounce cup. The medium cup is full to the brim.

2. The contents of the medium cup, being poured into the large cup...

3. And behold, the large cup is also filled to (almost) the brim...where are the extra four ounces?

Public, we have been had!

HOPEFULLY there is a reasonable explanation that our math and logic-inhibited brains aren't catching, because Think, despite its Moleskine/Mac Pack clientele, is definitely one of the best coffee houses in the city.

Check out the video experiment here, and until Think offers an explanation/an extra four ounces, save yourself the extra forty cents!